Stewart's non-fiction writing career began with The Busker's Guide to Europe, and went on to include humour and travel books such as the student classic Don't Lean out of the Window! He is the author of a series of writing guides that includes How to be a Writer and How to Get Published. He has written for Pokémon, Ricky Gervais, and the Edinburgh Fringe. Other works include The Key to The Da Vinci Code and The Mystery of Rennes-le-Chateau. His books have been translated into more than a dozen languages. His debut novel, The Sphinx Scrolls, is the first in a series of archaeological/historical thrillers. Look out for the sequel, The Dali Diaries, coming soon!